/* $Id$
 *
 * This is LL(1) grammar for grammars used in LFC based on the "Introduction to
 * LFC Programming Language" (January 25, 2008) by Zhen Lixiao 
 */

%token LANG RANG
%token LBRACKET RBRACKET
%token TO VBAR TILDA
%token BLANK
%token IDENTIFIER STRING

%%

grammar : /*empty*/
        | production grammar_rest
	;

grammar_rest : /*empty*/
             | BLANK grammar
             ;

production : ordinary_production
           | non_token_production
           ;

ordinary_production : LANG IDENTIFIER RANG TO terms ;

non_token_production : LBRACKET IDENTIFIER RBRACKET TO terms ;

terms : term terms_rest ;

terms_rest : /*empty*/
           | VBAR terms
           ;

term : item item_rest ;

item_rest : /*empty*/
          | term
          ;

item : TILDA
     | LANG IDENTIFIER RANG
     | STRING
     ;